1. Field of the Invention
Embodiments of the present disclosure relate to a direct current (DC) voltage conversion circuit, and more particularly, to a DC voltage conversion circuit in a liquid crystal display.
2. General Background
DC voltage conversion circuits are widely used in portable liquid crystal displays to drive power supplies. In general, a portable liquid crystal display needs a stable 8 volt DC power supply and a stable 3.3 volt DC power supply.
In these systems, the DC voltage conversion circuits may include a plurality of voltage regulating circuits to output both positive and negative DC voltage for a liquid crystal display. However, in order to output a negative output voltage, a negative charge pump may be positioned between a power supply and an output of the DC voltage conversion circuit. These negative charge pumps are generally very expensive and create an additional cost for a manufacturer of a liquid crystal display. FIG. 3 shows one example of a DC conversion circuit of the prior art with a first voltage regulating circuit 12 and a second voltage regulating circuit 14. As mentioned above, a negative charge pump 121 may be positioned between a power supply 11 and a first output 15.
From the foregoing, it should be appreciated that there is a need for a DC voltage conversion circuit that generates at least one negative output voltage and at least one positive output voltage. To this end, there is a need for a DC voltage conversion circuit that may generate at least one negative output voltage and at least one positive output voltage whereby the above-described shortcomings are overcome or at least mitigated.